Granular flow stimulating devices



Jan. 30, 1968 2 Sheets-Sheet 1 Filed April 25, 1966 INVENTOR Doueus H.Lucas ATTORNEYS D. H. LUCAS GRANULAR FLOW STIMULATING DEVICES Jan. 30,1968 Filed April 25, 1966 2 Sheets-Sheet um! I mu INvEN-rQR DoueLAs H.Lucas United States Patent Ofifice 3,366,282 GRANULAR FLOW STIMULATINGDEVICES Douglas Harold Lucas, Beneath the Bough, 38 Lodge Close, StokedAbernon, Cobham, England Filed Apr. 25, 1966, Ser. No. 544,968 Claims.(Cl. 222-195) ABSTRACT OF THE DISCLOSURE In a container for granularmaterial such as coal a flow stimulating device is provided. This devicecomprises an elongated tube mounted for movement adjacent to andparallel with at least a part of the interior wall surface of thecontainer. The tube has a plurality of apertures through whichcompressed air is blown. Means is provided for maintaining the aperturesin a direction such that the compressed air is blown in directionssubstantially parallel with the interior surface of the container tostimulate flow adjacent the surface.

This invention relates to the stimulation of the flow of granularmaterial, for example flow under the influence of gravity, in acontainer for the granular material and is particularly, though notexclusively, applicable to stimulating the gravity flow of coal from acontainer such as a bunker or hopper.

It has already been proposed to inject compressed air into a containerfor granular material through nozzles projecting through the containerwalls into the interior of the container. However, these nozzles arestationary and the eifect of the compressed air is restricted to thevicinity of the outlets. If flow of the granular material is to bemaintained throughout the bunker a very large number of nozzles will benecessary and large volumes of compressed air will be required. Thus theprior system is inefficient and expensive.

According to the present invention a container for granular material isin combination with a flow stimulating device comprising an elongatedmember, admission means for admitting pressurized gas to the interior ofthe elongated member, the elongated member having a number oflongitudinally spaced laterally directed apertures for the emission ofcompressed gas into granular material in the container, the elongatedmember being mounted on the container by mounting means permittingmovement of the elongated member about the interior of the container.

In most embodiments there will be a number of longitudinally spacedapertures in the elongated member.

The flow stimulating device may include means for delivering blasts ofcompressed gas through the apertures in sequence. Thus there may hemeans for opening and closing the apertures in sequence. The device maybe connected to a supply of compressed air at substantially constantpressure and the means for opening and closing the apertures may be usedas the sole means for controlling the emission of gas. In an alternativearrangement the escape of compressed air may be controlled additionallyor solely by valve means adapted to permit compressed gas to flowthrough it in short blasts. The means for opening and closing theapertures in sequence will then act chiefly or solely to determine whichof the apertures is to be used for the escape of gas when the valvemeans releases a blast of compressed gas.

The device may be controlled by a timing mechanism which causes thedevice to operate for a short period of time at fairly long intervals oftime and there may also be provided an emergency device which causes thedevice to operate at any other time if the flow of material from thecontainer fails or falls below a certain figure.

Patented Jan. 30, 1968 In one form, the mounting means permits theelongated member to traverse around the interior surface of thecontainer parallel to and close to this surface, but the mounting meansmay permit movement of the elongated member over substantially the wholeof the interior of the container. One suitable arrangement permittingsuch movement is constituted by a travelling gantry arrangement to whichthe upper end of the elongated member is attached. Alternatively, themounting means may limit movement of the elongated member to traversingaround or across the interior surfiace of the container. A possible formof such mounting means comprises a rail which extends around thecontainer and on which the elongated member is carried.

The invention may be performed in various ways and a number ofembodiments will now be described by way of example with reference tothe accompanying drawings in which:

FIGURE 1 is a diagrammatic cross-section through a rectangular bunker inwhich is mounted a flow stimulating device;

FIGURE 2 is a fragmentary front view to a larger scale of the tubes ofthe flow stimulating device shown in FIGURE 1;

FIGURE 3 is a fragmentary side view of the tubes shown in FIGURE 2;

FIGURE 4 is a fragmentary sectional view to a further enlarged scale ofthe lower part of the tubes shown in FIGURES 2 and 3;

FIGURE 5 is a diagrammatic cross-section through another rectangularbunker;

FIGURE 6 is a fragmentary section to a larger scale on the line A-A inFIGURE 5;

FIGURE 7 is a fragmentary section to a further enlarged scale on theline BB in FIGURE 6; and

FIGURE 8 is a diagrammatic cross-section through a circular bunker.

Referring now to FIGURES 1 to 4 of the drawings, there is shown arectangular bunker 1 containing granular coal 2 which flows undergravity through an opening 3 at the bottom of the bunker. Each end ofthe bunker is provided with a rail 4 on which is mounted a gantry 5which extends the length of the bunker and can be moved from side toside of the bunker on wheels 6 which run on the rails 4.

Mounted on the gantry 5 by wheels 7 is a carriage 8 which can be movedfrom end to end of the gantry. Thus the carriage 8 can be positionedabove any part of the bunker. Carried on gimbal mountings on thecarriage 8 is a granular flow stimulating device 9 which includes anouter tube 10 and an inner tube 11 which is mounted for reciprocationwithin the outer tube. The outer tube is provided with a number ofdownwardly inclined short pipes 12 arranged in oppositely disposedpairs, the pipes being formed as nozzles as can be seen from FIGURE 4.The pipes are in communication with the interior of the outer tube 10through holes 13.

The inner tube 11 has a number of pairs of openings 14 corresponding tothe holes 13 in the outer tube although, as will be seen from FIGURES 2and 3, their spacing is slightly different.

The carriage 8 supports a geared electric motor 20 which drives a screw21 which passes through an internally threaded cap 22 at the upper endof the inner tube 11. When the motor 20 is rotated in one direction theinner tube 22 will be raised relative to the outer tube and when themotor is rotated in the opposite direction the inner tube will belowered relative to the outer tube. Limit switches, which are not shown,are provided for reversing the motor at the end of travel of the innertube so that the inner tube is reciprocated within the outer tube.

The inner tube is in communication through a flexible 3 tube 25 with acompressed air main 26 the outlet from which contains asolenoid-operated valve 27.

When stimulation of the flow of the coal in the bunker is required, thesolenoid-operated valve 27 is opened to admit compressed air to theinterior of the inner tube 11 and the motor is switched on toreciprocate the inner tube. In the relative positions of the two tubesshown in FIGURES 2, 3 and 4, jets of air will be emitted through thelowermost pair of pipes 12. As the inner tube moves upwardly the supplyof air to the lowermost pair of pipes 12 will be cut off and compressedair will then be emitted from the pair of pipes immediately above thelowermost pair. During the upward travel of the inner tube gas will beemitted in succession from the pairs of pipes 12 and the reverse willoccur as the inner tube moves downwardly. In order to stimulate the flowof coal throughout the bunker, the stimulator is preferably moved alongparallel to and close to the sides of the bunker and the lower end ofthe stimulating device is kept out of contact with the internal surfaceof the bunker by projections 28 on the lower end of the outer tube 10.Automatic means may be provided for traversing the stimulating deviceover the surface of the bunker and for rotating the inner and outertubes through 90 at each corner of the bunker so that the blasts of airemitted through the pipes 12 will be parallel to the adjacent surface ofthe bunker. There may also be occasions, for example when compacted coalhas formed a thick layer on the walls of the bunker, when the stimulatoris best operated close to the centre of the bunker in the position shownin FIGURE 1.

In an alternative mode of operation the valve 27 is synchronized withthe movement of the inner tube 11 so as to be opened only when a pair ofapertures 13 and 14 are fully open. Thus the inner tube acts chiefly toselect the apertures in the outer tube through which blasts ofcompressed air controlled by the valve 27 are emitted.

As shown in FIGURE 4, flanges 3t and 31 extend around the circumferenceof the inner tube immediately above and immediately below each pair ofapertures 14 in order to restrict the loss of gas between the inner andouter pipes.

Various modifications to the construction described may be made, and anumber of these will now be briefly described. Instead of the traversingarrangement comprising rails at each end and a gantry carrying acarriage, the stimulating device may be carried on a single rail whichextends all round the bunker. This construction is particularly suitablefor bunkers of circular section. The flow stimulating device may beconstructed so that it may be moved from bunker to bunker as required.It is not necessary for the inner tubes to be continuous and a possibleconstruction is for the inner tube to be made up of a number of hortsections, each section being in the vicinity of a hole or holes in theouter tube, and connecting pieces extending between adjacent sections.In place of the electrical reciprocating means described, hydraulicmeans comprising a double-acting piston could be adopted. A compressedair reservoir may be provided adjacent the stimulating device to providea store of compressed air to maintain the energy of the blasts of gasemitted through the holes, if a flexible pipe of relatively small boreis used to supply compressed gas.

The bunker shown in FIGURE 5 is of rectangular crosssection and is builtfrom steel plate. The bunker contains granular coal 42 which falls undergravity through an opening 43 at the bottom of the bunker. One end wallof the bunker, which is viewed in elevation in FIGURE 5, has a flowstimulating device 44 which comprises a tube 45 which is closed at oneend 46 and has a right-angled bend 47 at the other end leading to ashort straight section 48 which projects through an aperture 49 in theend wall of the bunker. The aperture 49 is closed by a mounting plate 51secured to the bunker wall by screws 52. The plate 51 carries a bearing53 in which the tube section 48 can rotate about an axis 54 which isperpendicular to the end wall of the bunker. Fixed to the pipe section48 is a Worm wheel 55 meshing with a worm 56 driven through a reductiongear box by an electric motor 57 mounted on the end wall of the bunker.At the outer end of the pipe section 48 is a stufling gland 58 whichconnects the rotatable pipe section 48 with the end of a stationary pipe59 through which compressed air may be supplied to the rotatable pipe.

The tube 45 carries a number of nozzles 61 which can be seen in moredetail in FIGURE 7. Each nozzle 61 projects through the wall of the tube45 from a solenoid operated valve 62 having a control solenoid 63 and aninlet 64 which is open to the interior of the pipe 45. As the solenoidoperated valve is a common article of commerce it will not be describedin detail. The solenoid can be actuated through leads 65 which extendalong the length of the tube 45 and pass out of the stationary pipe 59through a seal 66 to a switch control system not shown.

The operation of the apparatus shown in FIGURES 5 to 7 is as follows.Compressed air is supplied through the stationary pipe 59 to the pipe45, which, in normal opera tion of the bunker, is stationary with allthe solenoid operated valves 62 closed. At predetermined intervals oftime, or when a blockage is suspected, the electric motor 57 isenergised and the tube 45 is caused to oscillate through a sectorindicated by the chain-dotted line 67 in FIGURE 5. The solenoid operatedvalves 62 are opened in a sequence controlled by the switching system,each valve being opened for short periods of time during which strongbursts of air are blown into the bunker. It will be seen from FIGURE 5that substantially the whole of the end face of the bunker will besubjected to transverse bursts of air as the pipe 45 traverses the face.A similar granular flow stimulating device will be provided on thebunker face opposite to that visible in elevation in FIGURE 5 andsimilar devices may also be provided on the other two faces if required.

The axis of rotation 54 may alternatively be located at various otherpoints on the end face of the bunker. For example, the axis may passapproximately through the centre of the face and in this case the tube45, which will be shorter than that shown in FIGURE 5, may rotatethrough 360 about the axis instead of oscillating through a short are.In another possible arrangement the axis 54 is adjacent the mouth of theopening 43 and the tube 45 extends upwardly and oscillates between endpositions in which it lies parallel with the two side Walls of thebunker.

The bunker shown in FIGURE 8 is generally conical, the inner surface ofthe bunker being generated by a straight line about an axis 72. Thebunker 71 has an outlet 73 which is slightly eccentric to the axis 72. Agranular flow stimulating device 74 comprises a tube 75 having a bend 76and a short straight section 77 co-axial with the axis 72 of the bunker.The section 77 extends into a housing 78 which contains mounting means,driving means and connecting means similar to those shown in FIGURE 6.The upper end of the tube 75 carries a roller 79 engaged with the innerface of the bunker. In operation the granular flow stimulating device 74rotates about the axis 72 and thus traverses the inner surface of thebunker wall. During this time bursts of air are admitted to the bunkerthrough nozzles 81 along the length of the tube 75.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a container for granular material having a flow stimulating devicecomprising an elongated member and admission means for admittingcompressed gas to the interior of the elongated member, the elongatedmember having a number of longitudinally spaced apertures for theemission of compressed gas into granular material in the container, theimprovement comprising mounting means by which the elongated member ismounted on the container, said mounting means comprising meanspermitting movement of the elongated member along a path adjacent to andparallel with at least a part of the interior wall surface of thecontainer, and means for maintaining said apertures oriented to directsaid compressed gas in directions substantially parallel with saidsurface.

2. A container as claimed in claim 1 in which the flow stimulatingdevice includes means for controlling the delivery of compressed gasthrough the apertures whereby compressed gas is delivered through theapertures in sequence.

3. A container as claimed in claim 1 including valve means in thecompressed gas admission means adapted to permit compressed gas to flowthrough it in short blasts.

4. A container as claimed in claim 1 in which each aperture has asolenoid-operated valve housed within the elongated member.

5. A container as claimed in claim 1 in which the means permittingmovement of the elongated member permits movement about substantiallythe entire interior Wall surface of the container.

6. A container as claimed in claim 5 in which the mounting means isconstituted by a travelling gantry arrangement to which the upper end ofthe elongated member is attached.

7. A container as claimed in claim 1 in which the elongated member has apipe section at one end which is at an angle "to the longitudinal axisof the elongated member and is rotatably mounted in a fixed support onthe container.

8. A container as claimed in claim 7 in which the pipe section is normalto the longitudinal axis of the elongated member and to the part of theinterior wall surface of the container in the vicinity of the fixedsupport.

9. A container as claimed in claim 7 in which the interior wall surfaceof the container is a surface of revolution, the pipe section beingcoaxial with the axis of generation of the surface and the elongatedmember being parallel with a generatrix of the surface.

10. A container for granular material and a flow stimulating device asclaimed in claim 7 in which each aperture has a solenoid-operated valvehoused Within the elongated member.

References Cited UNITED STATES PATENTS 3,166,222 1/1965 Schrader 222-FOREIGN PATENTS 468,567 7/ 1937 Great Britain.

ROBERT B. REEVES, Primary Examiner.

F. R. HANDREN, Assistant Examiner.

